EvoSPL is back. 5
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From: Turkey Town (Gobble-Gobble)
jsut to make a correction to some of my previous posts, I've been referring to the NHRA Sport compacts as IHRA..... disregard the IHRA reference
Last edited by 1QWKEVO; Dec 11, 2003 at 12:54 PM.
Originally posted by Guru_Del
man i had my wastegate open like that on my RRM turbo and i thought it was loud at 5 psi I can only imagine that sucker at 22 or whatever you wind up running hahahahah
AWSOME!!!!!!!
man i had my wastegate open like that on my RRM turbo and i thought it was loud at 5 psi I can only imagine that sucker at 22 or whatever you wind up running hahahahah
AWSOME!!!!!!!
Also, I had a 300zx with TWO of the HKS Racing wastegates, again open to the atmosphere...
George
Thanks for writing all that. I really do not have the time to post these long messages. 
George
I do not know why, but the Z guys still claim that a 2.5" exhaust is the most you need for a TD06-20G turbo...
george
George
I do not know why, but the Z guys still claim that a 2.5" exhaust is the most you need for a TD06-20G turbo...
george
Originally posted by ItsStockOfficer
No, hes wrong and now your wrong because, and allow me to make this clear, a turbo engine always operates with higher back pressure on the head then would ever be considered remotely optimal in any situation.
Also, we don't need to worry about increasing intake velocity, we can merely increase our boost. That page you liked to was by no means a definitive tuning guide for cams and exhaust systems and while it made a few good(though obvious to any tuner) points, it doen't mater a whole lot to us.
We want to do what ever we can to reduce back presure at the head. This is our form of parasitic loss, equivalent (although far less then) a superchargers. We do not get a free lunch, even with turbo's
So now that we have established that we want to reduce back pressure at the HEAD as much as possible, the question we have to ask here is, whats the best way of doing that.
First, lets quickly go over exhaust on a n/a car. Exhaust is never a constant stream of air, but is actually a series of high pressure pulses followed by vacuum(or at least area of far lower pressure). These pulses are pulled forward by the vacuum in front of them. If you go with an exhaust system that it simply to large, this harmonic system breaks down, and you lose power. Generally going to an overlarge exhaust system increase back pressure at the head, and makes you lose power that way. Not having enough back pressure is fairly uncommon on a street car.
On a turbo car, this theory does not really apply a whole lot for 2 reasons.
A. The turbocharger itself ruins the harmonic pulses and breaks down the system. It turns from a harmonic system to a sewer pipe. At that point, bigger is better.
B. Turbos spool based upon pressure differential. Higher in the turbine, faster spool, lower in the downpipe, faster spool. When you step on the gas with a full 3 inch O2 eliminator for instance, you are going to get boost significantly faster, and those few PSI are already adding far more power then any affect harmonics might have played (which is zero anyways.)
So on a turbo car, after the turbine wheel, bigger is better, and non existant is best. a larger exhaust will create more power at EVERY RPM. If you think Im wrong, feel free to dyno it yourself.
No, hes wrong and now your wrong because, and allow me to make this clear, a turbo engine always operates with higher back pressure on the head then would ever be considered remotely optimal in any situation.
Also, we don't need to worry about increasing intake velocity, we can merely increase our boost. That page you liked to was by no means a definitive tuning guide for cams and exhaust systems and while it made a few good(though obvious to any tuner) points, it doen't mater a whole lot to us.
We want to do what ever we can to reduce back presure at the head. This is our form of parasitic loss, equivalent (although far less then) a superchargers. We do not get a free lunch, even with turbo's
So now that we have established that we want to reduce back pressure at the HEAD as much as possible, the question we have to ask here is, whats the best way of doing that.
First, lets quickly go over exhaust on a n/a car. Exhaust is never a constant stream of air, but is actually a series of high pressure pulses followed by vacuum(or at least area of far lower pressure). These pulses are pulled forward by the vacuum in front of them. If you go with an exhaust system that it simply to large, this harmonic system breaks down, and you lose power. Generally going to an overlarge exhaust system increase back pressure at the head, and makes you lose power that way. Not having enough back pressure is fairly uncommon on a street car.
On a turbo car, this theory does not really apply a whole lot for 2 reasons.
A. The turbocharger itself ruins the harmonic pulses and breaks down the system. It turns from a harmonic system to a sewer pipe. At that point, bigger is better.
B. Turbos spool based upon pressure differential. Higher in the turbine, faster spool, lower in the downpipe, faster spool. When you step on the gas with a full 3 inch O2 eliminator for instance, you are going to get boost significantly faster, and those few PSI are already adding far more power then any affect harmonics might have played (which is zero anyways.)
So on a turbo car, after the turbine wheel, bigger is better, and non existant is best. a larger exhaust will create more power at EVERY RPM. If you think Im wrong, feel free to dyno it yourself.
Last edited by Boost Solutions; Dec 11, 2003 at 01:31 PM.